<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>H5触摸事件</title>
</head>
<body>
<p>判断滑动方向</p>
<div id="mybody" style="height: 300px;background-color: #6D7273"></div>
</body>
<script>
    var mybody = document.getElementById('mybody');

    //返回角度
    function GetSlideAngle(dx, dy) {
        return Math.atan2(dy, dx) * 180 / Math.PI;
    }

    //根据起点和终点返回方向 1：向上，2：向下，3：向左，4：向右,0：未滑动
    function GetSlideDirection(startX, startY, endX, endY) {
        var dy = startY - endY;
        var dx = endX - startX;
        var result = 0;
        //如果滑动距离太短
        if (Math.abs(dx) < 2 && Math.abs(dy) < 2) {
            return result;
        }
        var angle = GetSlideAngle(dx, dy);
        if (angle >= -45 && angle < 45) {
            result = 4;
        } else if (angle >= 45 && angle < 135) {
            result = 1;
        } else if (angle >= -135 && angle < -45) {
            result = 2;
        } else if ((angle >= 135 && angle <= 180) || (angle >= -180 && angle < -135)) {
            result = 3;
        }
        return result;
    }

    //滑动处理
    var startX, startY;
    mybody.addEventListener('touchstart', function (ev) {
        ev.preventDefault();
        startX = ev.touches[0].pageX;
        startY = ev.touches[0].pageY;
    }, false);
    mybody.addEventListener('touchend', function (ev) {
        var endX, endY;
        ev.preventDefault();
        endX = ev.changedTouches[0].pageX;
        endY = ev.changedTouches[0].pageY;
        var direction = GetSlideDirection(startX, startY, endX, endY);
        switch (direction) {
            case 0:
                alert("没滑动");
                break;
            case 1:
                alert("向上");
                break;
            case 2:
                alert("向下");
                break;
            case 3:
                alert("向左");
                break;
            case 4:
                alert("向右");
                break;
            default:
        }
    }, false);
</script>
</html>